Traditionally caster wheels have been used to provide wheeled support for a wide range of items for which mobility is desirable. Examples of such items include pianos, fridges, tea trolleys, supermarket trolleys and various other work-related or domestic items. The caster wheel comprises a single wheel rotatable about a generally horizontal axis, which horizontal axis is in turn mounted to a substantially vertical axis about which the hole unit pivots. The caster wheel generally acts as a follower, thereby enabling a wheel to travel in any direction in which it is pulled. Caster wheels are generally made of multiple components made of different materials and may require a costly and difficult manufacturing process. Moreover, the caster wheel is generally mounted on the object to be moved by its vertical axis making the attachment of the wheel to the object sometimes difficult to achieve.
More recently, another type of wheel capable of multiple directional travel has been considered and includes a central hub rotatable about a main axis and a plurality of independently mounted rotatable rollers located about the rim of the hub. The rollers are each capable of rotation about an axis transverse to the main axis whereby the wheel is capable of moving in a first direction in which the wheel rotates about the main axis or in a transverse direction in which one or more rollers contacting the ground rotate about their one or more axes.
However, the above described wheel is poorly adapted for transverse travel that there is virtually no overlap between diagonally adjacent rollers. The difficulty in placing the rollers closer together has proved a significant obstacle to the viability of such wheels. The combination of factors including the diameter, number and length of the rollers are important. The inner ends of the rollers cannot be so close as to interfere with one another, whereas the outer ends are spaced too far apart to provide a sufficiently continuous ground contacting surface. Moreover, this prior art wheel is difficult and time-consuming to manufacture due to the number of components involved and the time required for assembly.
The above description of the prior art is not intended to be, nor should it be interpreted as, an indication of the common general knowledge pertaining to the invention, but rather to assist the person skilled in the art in understanding the developmental process which lead to the invention.
It is proposed to provide a multiple directional wheel which ameliorates one or more of the disadvantages of the prior art or at least provides a useful alternative thereto.